Implicit signalling method for bearer management

ABSTRACT

Implicit signalling method for bearer management in a communication network with transporting bearer resource request message of both the UE and RN via Base station to managing entity of RN within EPC, as a signalling message over uplink channel referred to as ‘Union of Resource Request (UR Request)’ message. The bearer resource response message referred to as ‘Implicit Admission Response (IA Response)’ from one of the management entity of UE or management entities of UE and RN within EPC are transported as a signalling message to Evolved Packet Edge (EPE) via Base station over the downlink channel. This manages bearer setup signalling as a single loop, by transportation of ‘UR Request’ signalling message and receiving one “IA Response” signalling message over uplink and downlink channels respectively. EPE is a conglomeration of network nodes made of UEs, RNs and all other network nodes that communicate over EPC via Base station.

FIELD OF THE INVENTION

The present disclosure relates to bearer management in a wirelesscommunication network. In particular, the invention relates to transportof signalling messages on the interface between a relay node and anothernode in a mobile communication network.

BACKGROUND

In order to provide better qualities of service and wider communicationranges between wireless nodes, the concept of relay station has beenintroduced in network systems. The purpose of deploying relay station orRelay Node (RN) in network system is to extend the serving coverage ofBase station (eNB); hence, user equipment (UE) which is not within thecommunication coverage of Base station can access the services providedby relay node as well via Base station.

Wireless network architecture as defined by 3GPP introduces wirelessrelay node (RN) entity to extend the coverage of Base station (evolvedNode B or eNodeB or eNB). A long term evolution-advanced (LTE-A) system,as its name implies, is an evolution of the LTE system, consideringrelaying for cost-effective throughput enhancement and coverageextension. For example, a relay can be deployed at the cell edge wherethe Base station is unable to provide required radio quality/throughputfor the UEs or at certain location where radio signals of the Basestation cannot cover.

The Relay Node (RN) forms an independent physical cell. From a userequipment (UE) perspective, the RN is seen as a usual Base station. TheRN is connected via a wireless link to the Base station. The relay nodearchitecture deployment foresees that a RN emulates a Base station forthe UE, which means that the UE would see the RN as a usual Basestation. From the network side, the RN is seen as a usual UE by the Basestation. The Base station or eNB, to which the RN is connected, iscalled Donor-eNB (DeNB) hereinafter referred to as Base station or eNBand operates as a usual Base station. The deployment of RN in the 3GPPnetwork architecture is described in 3GPP Technical Specification36.806; “Relay architectures for E-UTRA (LTE-Advanced)”.

In order for the user equipment to receive a service from the network,it needs to establish connectivity via Base station, by initiatingNon-Access Stratum (NAS) signalling messages with network nodes likeMobility Management Entity (MME) serving the UE. Consequentialsignalling messages are exchanged between network nodes to allocatebearer resources for UE and RN to service the UE request. The abovebearer management procedure can be initiated by UE or the Evolved PacketCore (EPC in terms of 3GPP LTE) or simply the communication network.Similar procedures are followed for managing existing bearers. Themanaging functions include creating new entry, updating and deleting.

Thus, whenever a UE bearer is created or modified, the RN bearer modifyor create procedures may be initiated by the RN. This increases theexchange of messages separately for the UE and for the RN tomodify/create a new bearer. Thus additional messages may be exchanged bythe RN each time a bearer is created/modified for the UE, leading todelayed access service and as well as backhaul bandwidth is wasted orunderutilized. Therefore, there is a need for a bearer management tooptimize radio and backhaul resources by effectively setting-up thebearers.

SUMMARY OF THE INVENTION

The summary represents the simplified condensed version of the claimedsubject matter and it is not an extensive disclosure of the claimedsubject matter. The summary neither identifies key or critical elementsnor delineates the scope of the claimed subject matter. The summarypresents the simplified form of the claimed subject matter and acts as aprelude to the detailed description that is given below.

The present invention and its embodiments are made to provide for afeasible solution for facilitating bearer management in a communicationnetwork optimizing exchange of signalling communication in managingbearers for UE and RN.

An aspect of the invention provides for a method of managing bearersignalling in a communication network, by transporting “Union ofResource Request” (UR Request) signalling message from Evolved PacketEdge (EPE) entities to managing entities of RN via Base station andreceiving “Implicit Admission Response” (IA Response) signalling messagefor the transported UR Request from management entity of UE by Basestation, wherein the said management entity serves/manages all theentities in the EPE. EPE is a conglomeration of network nodes comprisingof user equipment, relay nodes and all other network nodes thatcommunicate with EPC via Base station. Network nodes in the EPE mayestablish connectivity external to EPC like Internet or PSTN (PublicSwitch Telephone Network).

Another aspect relates to receiving “Implicit Admission Response” (IAResponse) signalling message for the transported UR Request frommanagement entity of UE by the Base station, wherein at least one of thesaid management entities are not serving/managing the same entities inthe EPE.

Another aspect relates to network nodes like RN, Base station, MME_RNand MME_UE and systems facilitating the above method of managing bearerseach comprising of at least a receiver, for receiving the said messages,processors for executing the functions, transmitter for transmittingmessages, a memory for storing information and retaining instructionsfor executing functions associated with the above methods.

Other aspects, advantages, and salient features of the invention willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses exemplary embodiments of the invention.

DESCRIPTION OF THE DRAWINGS

The features, advantages and other aspects of the embodiments of thepresent invention will be obvious to any person skilled in the art toappreciate the invention when read with the following description takenin conjunction with the accompanying drawings.

FIG. 1 is an illustration of existing bearer establishment procedure foruser equipments (UE) and relay node (RN) as specified in 3GPP LTE (A)network architectures.

FIG. 2 shows the network nodes conglomeration between two networkentities in accordance with the principles of the invention.

FIG. 3 represents ‘UR Request’ message signalling in the uplink fromEvolved Packet Edge to Evolved Packet Core via Base station inaccordance with the embodiments of the invention.

FIG. 4 shows a detailed method of tagging (UE_TAG) in any one of thecontrol plane protocol layers in accordance with the embodiments of theinvention.

FIG. 5 represents bearer establishment signalling loop in accordancewith various aspects of the invention.

The figures are not drawn to scale and are illustrated for simplicityand clarity to help understand the various embodiments of the presentinvention. Throughout the drawings it should be noted that likereference numbers are used to depict the same or similar elements,features and structures.

DETAILED DESCRIPTION

The following descriptions with reference to the accompanying drawingsare provided to assist in a comprehensive understanding of exemplaryembodiments of the invention as defined by the claims and theirequivalents. Accordingly, those of ordinary skill in the art willrecognize that various changes and modifications of the embodimentsdescribed herein can be made without departing from the scope and spiritof the invention.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of theinvention. The terms, component, module, system, and the like areintended to refer to an entity or entities within a communicationnetwork node comprising of; hardware, software, a combination ofhardware and software. For e.g., a component may be, but not limited tobeing, a process running on a processor, a processor, an integratedcircuit, or a computer. Both an application running on a computingdevice and the computing device can be a component. A component may belocalized on one computer and/or distributed between two or morecomputers. The components may communicate by way of local and/or remoteprocesses.

The present invention and its embodiments are mainly described inrelation to 3GPP specifications and standards (LTE-Advanced) forapplicability of certain exemplary embodiments. The terminology used istherefore related thereto. Such terminology is used in the context ofdescribing the embodiments of the invention and it does not limit theinvention in any way. Any other network architecture or systemdeployment, etc., may also be utilized as long as it is compliant withthe features described herein.

In particular, embodiments of the present invention may be applicable inany relay-enhanced (cellular) system with a need for signallingoptimization. Embodiments of the present invention may be applicablefor/in any kind of modern and future communication network including anymobile/wireless communication networks/systems.

The following paragraphs will describe various embodiments of theinvention. For exemplary purposes only, most of the embodiments areoutlined according to the LTE-Advanced mobile communication system withthe solution to the problem discussed in the background. It should benoted that the invention may be advantageously used in connection withthe communication system described above, but the invention is notlimited to its use in this particular exemplary communication network.The explanations given below are intended to better understand specificexemplary embodiments described herein and should not be understood aslimiting the invention to the specific implementations of processes andfunctions in a mobile communication network. The improvements/solutionsproposed herein may be readily applied in architectures/systems havingrelevance to relay architectures. Some embodiments of the invention mayalso make use of standard and improved procedures of thesearchitectures/systems.

The techniques described herein may be used for various wirelesscommunication networks such as CDMA networks, CDMA implementing radiotechnology such as UTRA, TDMA networks, TDMA implementing radiotechnology such as GSM, FDMA networks, OFDMA networks, OFDDAimplementing radio technology such as Evolved URTA (E-UTRA), SC-FDMAnetworks.

User equipment (UE) used in the following description denotes variousterminologies used like an access terminal (AT), wireless communicationdevice, terminal, wireless handset, computer or wireless module,wireless module for use with a computer, personal digital assistant(PDA), tablet computer or device.

In the overall architecture of a network with a relay node (RN), a relaynode has a Base station (Base station) and a terminal side called asuser equipment (UE). Towards UE the RN behaves as a conventional Basestation using the access link (Uu interface) and the UE is not aware ofwhether it is communicating with a relay node or a Base station. Relaynodes are therefore transparent for the UE. Towards Base stations relaynodes initially operate as a UE using the radio interface to connect tothe Base station. Once connection is established and the relay node isconfigured, the relay uses a subset of the UE functionality forcommunication on the backhaul link (Un interface).

The UEs are connected to the RN by means of an Uu interface and the RNto the Base station by means of Un interface. When the network e.g., MMEhas no valid location or routing information for the UE, the UE cannotbe reached. This is more likely when the UE is in a state of switchedoff, or out of coverage area. 3GPP defines this state as a de-registeredstate and this could also happen when the UE is in non-3GPP access. Whenthe UE is attached to the network e.g., MME, it can receive Core Networkservices. This state is defined by 3GPP as registered state. In thisregistered state the UE can be in two different connection managementstates like RRC_IDLE state and RRC_CONNECTED state. When no data isbeing transmitted and the radio resources are released, the UE has avalid IP configuration. In such idle state there is no Non-AccessStratum (NAS) signalling connection between the UE and the network,e.g., MME. Also during the idle state there is no S1 connection betweenthe Base station and the Serving Gateway. In the RRC_CONNECTED state,there is an active connection between the UE and Base station, whichimplies a communication context being stored within the Base station forthis UE. Both sides can exchange user data and or signalling messagesover logical channels.

From the wireless network perspective, protocol structure for the Userand Control planes correspond to user data transmission and signallingtransmission. Control plane corresponds to the information flowsactually considered as signalling by E-UTRAN and Core Network. Thisincludes all the RRC (Radio Resource Control) E-UTRAN signalling(supporting functions such as Radio Bearer management, radio mobility,user paging) and NAS (Non Access Stratum) signalling. On the radiointerface, the Control plane uses the Control plane protocol stacknamely PDCP (Packet Data Convergence Protocol), RLC (Radio LinkControl), MAC (Medium Access Control) and PHY (Physical) stack totransport both RRC and Core Network NAS signalling. The above protocolstack layers support the same functions for both the User and ControlPlanes. When a Non-Access Stratum (NAS) signalling connection needs tobe established between UE and the MME routed via relay node, the UE andthe MME shall enter the connected state.

It should be noted that Base station is in fact connected to one or morethan one MME or Serving GW node. These pluralities of Base station forma pool area such that a pool area can be served by one or several MMEand/or Serving GW. A given MME or Serving GW node may serve one orseveral pool areas. The connectivity of the relay node and the UEcommunicating via relay node, is managed by the network e.g., MME. Basedon initial NAS signalling, MMEs in the pool analyzes the request anddetermines which MME should manage the radio resources for therespective relay node or the UE communicating via relay node. Thiscommunication message essentially comprising of bearer requestacknowledgement, indicates the uplink channel through which the UE is tocommunicate for establishing radio bearers. For the sake of simplicityMME managing the UE and the MME managing the RN is indicated as MME_UEand MME_RN respectively, hereinafter.

FIG. 1 shows the signalling message for bearer initiation procedureexisting in 3GPP LTE specification. UE 20 sends an initial NAS messageor service request to the MME_UE 101 a, which is routed through RN 10and Base station 30. When a NAS layer in the UE has to send an initialNAS message denoted as ‘UE NAS Msg’ in FIG. 1, the UE first initiatesthe establishment of the Radio Resource Control (RRC) connection overthe Uu interface. The RRC procedures are elaborated in 3GPPspecification TS 36.331 available at www.3gpp.org. In parallel to theestablishment of the RRC connection over the Uu interface, the RNinitiates the establishment of the RRC connection over the Un interface.The RRC connection establishment procedure over the Uu and Un interfacesare identical.

The NAS message is directed to MME (UE) 101 a and the RN 10 istransparent. The MME_UE 101 a understands the message and forwards it tothe SGW/PGW_UE 102 a for checking the UE subscription data. Then theSGW/PGW_UE 102 a in conjunction with PCRF (not shown) authorizes MME_UE101 a to create a dedicated bearer and sends the message over S11interface (Interface between S/PGW and MME). On receiving the response,MME_UE 101 a sends bearer setup request to the UE 20 as an S1-AP messagerouted through RN 10. RN 10 understands this S1-AP message and initiatesRRC configuration between UE 20 and RN 10. A bearer setup response isthen sent by UE 20 to MME_UE 101 a routed via RN 10 and Base station 30as an S1-AP message. On receiving the response from UE 20, MME_UE 101 aestablishes the bearers and sends the response to SGW/PGW_UE 102 a. Thisprocess establishes radio bearers to enable data flow from theSGW/PGW_UE 102 a to the UE 20. After completion of this procedure, theRN 10 may send a NAS message seeking bearer-resource request to MME_RN101 b through Base station 30. MME_RN 101 b understands the message andprovisions bearer resource allocation to RN 10. Upon receiving bearerresource allocation, RN 10 bearer establishment is completed. Radioresources for the relay node 10 are allocated so as to serve the alreadyestablished UE's bearer requirements. The above process of initiatingbearer establishment can also be initiated by EPC/Core Network. Thishappens both when the UE 20 is in the RRC_IDLE state and a message/datais to be transported to the UE 20 by the Core Network or when there is achange in existing bearer configuration to the UE 20 in theRRC_CONNECTED state. In this state, MME_UE 101 a initiates bearer-setupor modify procedure for the UE 20 at any point of time based on UEsubscription and QoS requirements. Thus in all the above instances of UENAS Messages, whenever a UE 20 bearer is created or modified, the RNbearer, modify or create may be initiated subsequently by the RN 10.Thus additional messages are exchanged separately for the UE 20 and forthe RN 10 to modify/create a new bearer. This either wastes orunderutilizes the backhaul bandwidth. Further, there is delay in trafficflow.

FIG. 2 shows the network nodes conglomeration between two networkentities in accordance with the principles of the invention. Networkentity 625 is called as Evolved Packet Edge (EPE) comprising ofplurality of network nodes like UE, RN and all other nodes thatcommunicate with Evolved Packet Core Network entity 675 via Base station30. Network nodes in the EPE 625 may establish connectivity external toEPC like Internet 106 or PSTN (Public Switch Telephone Network) 107. EPCentity 675 comprises of network nodes like Mobility Management Entity(MME), Serving gate way/Packet gate way (S/PGW), Policy of ChargingRules Function etc., These nodes essentially manages the entities in theEPE. For e.g., a UE bearer resource request is processed and allowedonly by the MME serving the UE. Depending on the complexity of thecommunication network, it so happens that, MMEs are segregated toperform management of plurality of UE and RN separately. In such cases,it is appropriate to indicate MMEs serving the UEs as MME_UE and MMEsserving the RNs as MME_RN.

As part of bearer management signalling as envisaged, a communicationfrom EPE 625 comprising of bearer resource request of both the UE and RNis transported via Base station 30 to EPC as a single signalling messageover uplink channel 651 hereinafter referred to as “Union of ResourceRequest” (UR Request) message. The response message comprising of bearerresource response from either one of the managing entity or managingentities of EPC 675 are transported as a single signalling message toBase station 30 over the downlink channel 652 hereinafter referred to as“Implicit Admission Response” (IA Response). This manages bearer setupsignalling loop, with a single transportation of ‘UR Request’ signallingmessage and receiving one “IA Response” signalling message over uplinkand downlink channels respectively.

FIG. 3 represents “UR Request” message signalling in the uplink from EPE625 to EPC 675 via Base station 30 in accordance with the embodiments ofthe invention. When the UE 20 is in the state of RRC_CONNECTED orRRC_IDLE; a UE NAS signalling message requesting bearer resource of theform ‘Create, Update, Detach, Modify’ etc., hereinafter referred to as“CRUD” messages, are generated. It so happens that, depending on thecomplexity of the EPE communication network, multiple relay nodes may bewirelessly connected in a sequence so as to serve a distant UE. In suchcases, a bearer request of a UE initiated by sending a UE NAS message tothe MME in the EPC 675 has to be routed via all the relay nodes actingin sequence. Such an arrangement is shown towards the right of EPE 625.

The UE NAS message generated by UE 20 is received at the first upstreamrelay node (RN). The first relay node encapsulates the said received UENAS message in the RN1 NAS message by adding the identity of UE (UE_ID).The RN1 NAS message thus created by first relay node is received by thesecond upstream relay node, which encapsulates the said received RN NASmessage in its RN2 NAS message by adding the identity of the downstreamrelay node (RN1_ID) as this RN is the UE for the upstream relay node.Relay node identity or RN_ID is a unique identifier that uniquelyidentifies the MME serving the said RN. Relay node identity comprises ofMME Group ID, MME code of MME_RN. The encapsulated RN2 NAS message isreferred to as tagged message (UE_TAG) and represented as “UR Request”.Similar tagging is done for any number of such upstream relay nodes. Theabove said tagged message is forwarded to the managing entity of RNwithin EPC 675 via Base station 30. The tagged message is available atthe MME_RN within EPC as “UR Request” message.

In case of a single relay node, encapsulated ‘RN NAS message with UE_ID’forms the tagged message. Depending on the mobility of the UE within EPEof a communication network, it so happens that, a single UE may beconnected to different relay nodes. Such circumstances may arise basedon the mobility of the UE and/or proximity of the UE with a RNexhibiting excellent signal strength. In such cases, a bearer request ofa UE initiated by sending a UE NAS message to the MME in the EPC 675 hasto be routed through the respective RN which is coupled to the UE. Suchan arrangement is shown towards the left of EPE 625.

FIG. 4 depicts protocol layers through which insertion of UE_TAG(comprising of UE_ID and type prefix for the said UE_ID) by the RN 10preferably at NAS layer or any one of the control plane protocol layersof S1-AP, SCTP, PDCP, RLC, MAC, PHY, is accomplished in accordance withthe embodiments of the invention. For the sake of illustration the flowof uplink signalling data in case of two radio bearers is shown withpossible UE_TAG insertion points, at any one of the protocol layers. Forthe sake of brevity, the control plane protocol layer 410 above PDCPlayer 401 is shown as an integrated layer comprising of NAS, S1-AP, andSCTP (Stream Control Transmission Protocol).

The PDCP layer 401 performs IP-header compression and ciphering. A PDCPheader is added, carrying information required for deciphering in theUE. The output from the PDCP is forwarded to the RLC layer 402. The RLCprotocol performs concatenation and/or segmentation of the PDCP ServiceData Units (SDUs) and adds an RLC header. The RLC Service Data Units(PDUs) are forwarded to the MAC layer 403, which multiplexes a number ofRLC SDUs and attaches a MAC header to form a transport block. Finallythe Physical layer 404 attaches a CRC (Cyclic Redundancy Check) to thetransport block for error-detection purposes and transmits the resultingsignal using transmit antennas. In the above protocol structure,possible insertion of UE_TAG 301 (shown by arrow headers) could be atany one of the layers. For e.g., UE_TAG 301 can be preferably insertedat header junction of layer 410, or at PDCP header junction of layer401, or at RLC header junction of layer 402 or at MAC header junction oflayer 403 or at any junction of the PHY layer 404. Similarly for eachradio bearer signalling flow a possible UE_TAG 301 could be inserted atany one of the protocol layers as explained above.

FIG. 5 represents bearer setup signalling loop, with a singletransportation of “UR Request” signalling message by EPE entities andreceiving one “IA Response” signalling message by Base station overuplink and downlink channels respectively, in accordance with theembodiments of the present invention. For the sake of simplicity, UEcoupled with one RN is shown. When the UE 20 is in the state ofRRC_CONNECTED (1) or RRC_IDLE (0), (Step 1) CRUD messages are generatedby UE or initiated by EPC. In either case, UE 20 generates either singleor multiple bearer resource requests within a single NAS message therebytriggering the establishment of RRC connection with the RN 10 in case UEis in RRC_IDLE (0) mode. RN 10 also starts the establishment of the RRCconnection with the Base station 30 in case RN is in RRC_IDLE (0) state.Both these RRC procedures over the respective Uu and Un interface areelaborated in 3GPP specification TS 36.331.

When the RN 10 receives the UE NAS Message (Step 2), relay nodeencapsulates the said received UE NAS message in the RN NAS message byadding the identity of UE (UE_ID) (Step 3) to be sent to the MME_RN 101b via Base station 30. Without loss of generality the denotation ‘UE NASMsg+UE_ID’ will be called as ‘UE TAG’ which means that it is a taggedmessage essentially consisting of UE NAS Message with UE_ID (Step 4).The above denotation is specifically defined for the purpose of thisinvention as a tagged message denoted as UE_TAG. In the case of multiplerelay nodes upstream (For e.g., RN1 and RN2), the first upstream relaynode RN1 encapsulates the said received UE NAS message in the RN1 NASmessage by adding the identity of UE (UE_ID) at any one of the controlplane protocol layers S1-AP, SCTP, PDCP, RLC, MAC, PHY preferably overNAS. The RN1 NAS message thus created by first relay node is received bythe second upstream relay node RN2, which encapsulates the said receivedRN1 NAS message in its RN2 NAS message by adding the identity of thedownstream relay node (RN1_ID) as this RN is the UE for the upstreamrelay node. The encapsulated RN2 NAS message is referred to as taggedmessage (UE_TAG) and represented as “UR Request”. Similar tagging isdone for any number of such upstream relay nodes

The UE_TAG is then transmitted from the RN 10 to the MME RN 101 b viaBase station 30 over Un interface as a control plane signalling message.When this UE_TAG arrives at Base station 30, Base station 30 understandsthe message to be a ‘UE TAG’ message except when tagged as NAS layer,and then forwards it to MME_RN 101 b; the MME_RN 101 b, understands themessage and if the tagged message is not a “UR Request” message ittreats as ‘other control plane signalling message’. If the taggedmessage is a CRUD message then the MME_RN 101 b de-capsulates UE 20 NASmessage and forwards the request to MME_UE 101 a using the identity ofUE. In case of multiple relay nodes (for e.g., RN1 & RN2), the RN2 NASmessage received by the Base station from the downstream relay node isforwarded to the mobility management entity serving the said downstreamrelay node (MME_RN2). The said MME_RN2 understands the received RN2 NASmessage and de-capsulates the message and forwards the RN1 NAS messageif found, within the said received RN2 NAS message to the mobilitymanagement entity serving the said relay node (MME_RN1) based on theidentity of relay node. MME_RN1 understands the received RN1 NAS messageand de-capsulates the ‘UE NAS message’ and forwards the ‘UE NAS message’along with the identity of MME_RN2 and any other MME_RN identities whichare in the sequence of receiving the RN NAS message to MME_UE based onthe UE identity inside RN1 NAS message (Step 5). The thumb rule forproviding the identities of MME_RN to next node is that, identities ofall MME_RNs via which the message has traversed except the identity ofthe node which is forwarding the message shall be provided to the nextMME node.

When the UE NAS message is received and understood by the MME_UE 101 ato be a bearer resource request message (Step 6), it grants utmost UErequest and generates relay node resource request (RR request) messagesfor granted resources by MME_UE. Thereafter a relay node resourcerequest (RR Request) message is generated, to be sent to MME_RN 101 b(Step 8). (In case of multiple relay nodes in sequence, MME_UE 101 agenerates relay node resource request (RR request) messages for grantedresources by MME_UE, for MME_RNs identified by MME_RN identities). Ifthe MME_UE 101 a does not grant UE 20 bearer request at step 7, thenMME_UE 101 a generates ‘UE NAS message for bearer resource reject’ andforwards it for UE 20 via Base station 30 (Step 13).

The ‘RR Request’ message generated by the MME_UE 101 a for MME_RN 101 bis a bearer request on behalf of RN 10. The message essentially is anestablishment of RN bearer to serve UE bearer QoS requirements. (Fore.g., the ‘RR Request’ message may be that some bandwidth is guaranteedfor the UE 20 which is being served by the RN 10 (RN_ID). Hence MME_RN101 b is required to process RN 10 bearer request). The ‘RR Request’ isthen forwarded to MME_RN 101 b. Once RN 10 bearer request is granted,MME_RN 101 b generates ‘RR Response’ message (Step 8). In case ofmultiple relay nodes, MME_UE forwards the granted resources of UE andforwards ‘RR Request’ messages to MME_RNs based on the identities ofRNs. The MME_RNs grants utmost ‘RR Request’ and generates ‘RR Response’message for the said received ‘RR Request’ messages and forwards thegenerated ‘RR Response’ message to the MME_UE. ‘RR Response’ messageincludes at least one among ‘RR Response Positive Ack’, ‘RR ResponseNegative Ack’.

If MME_RN 101 b grants at least partial ‘RR Request’, it generates ‘RRResponse Positive Ack’ and then forwards it to MME_UE 101 a. If theMME_RN 101 b does not grant ‘RR Request’ made by MME_UE 101 a, thenMME_RN 101 b generates ‘RR Response Negative Ack’, and then forwards itto MME_UE 101 a. MME_UE 101 a receives the ‘RR Response’ from the MME_RN101 b (Step 9) and processes it. ‘RR Response’ message received fromMME_RN 101 b is interpreted by MME_UE 101 a (Step 10). If the messagereceived is ‘RR Response Positive Ack’, then MME_UE generates andforwards to Base station “Implicit Admission Response Accept” (“IAResponse Accept”) message (Step 11). If the message received from MME_RN101 b is an ‘RR Response-Negative Ack’, then MME_UE generates andforwards to Base station “Implicit Admission Response Reject” (“IAResponse Reject”) message (Step 12). Once “IA Response Accept” messageis received by Base station, if required, it performs RRC configurationfor the downstream RN, which in turn performs RRC configuration for theremaining EPE entities (Step 14) if required. RRC procedures are similarto the procedures as elaborated in 3GPP specification TS 36.331.Implicit Admission Responses forwarded by MME_UE 101 a to Base stationmay be multiplexed, encapsulated or concatenated.

“Implicit Admission Response” that is available to Base stationcomprises of bearer resource allocation message pertaining to therespective EPE entities. For e.g., if MME_UE grants bearer resource (x)to the UE (Y), MME_UE generates ‘RR Request’ message seeking bearerallocation for the relay nodes (P, Q, R) and forwards to the respectiveMME_RNs. The ‘RR Request’ message may be in the form of Yx(P,Q,R).MME_RNs may grant the same resources ('x′) to the respective relay nodes(P,Q,R). In such cases “RR Response” message generated by MME_RNs may bex(P,Q,R). When this ‘RR Response’ message is received by MME_UE, MME_UEmay generate an “Implicit Response” in the form of x(Y). This “ImplicitResponse” is understood by the Base station as a message comprising ofallocated bearer resources corresponding to the value of ‘x’ to UE, andas a message comprising of allocated bearer resources corresponding tothe value of ‘x’ for the respective relay nodes ‘P’, ‘Q’ and ‘R’. In theabove example given, in case MME_RNs grants bearer resources for therelay nodes (P,Q,R) corresponding to the value less than the grantedvalue of UE i.e., ‘x-a’, then the ‘RR Response’ message that isgenerated by MME_RNs would be ‘x-a(P,Q,R)’. When this ‘RR Response’message is received by MME_UE, MME_UE may generate an “ImplicitResponse” in the form of ‘x-a(Y)’. This “Implicit Response” isunderstood by the Base station as a message comprising of allocatedbearer resources corresponding to the value of ‘x’ to UE, and as amessage comprising of allocated bearer resources corresponding to thevalue of ‘x-a’ for the respective relay nodes ‘P’, ‘Q’ and ‘R’. Furtherin the above given example, in case MME_RN managing ‘P’ grants bearerresources for the relay node ‘P’ corresponding to the value less thanthe granted value of UE i.e., ‘x-a’; and MME_RN managing ‘Q’ grantsbearer resources for the relay node ‘Q’ corresponding to the value lessthan the granted value of RN ‘P’ i.e., ‘x-b’; and MME_RN managing ‘R’grants bearer resources for the relay node ‘R’ corresponding to thevalue less than the granted value of RN ‘Q’ i.e., ‘x-c’, then the ‘RRResponse’ message that is generated by MME_RNs would be‘x-a,x-b,x-c(P,Q,R)’. When this ‘RR Response’ message is received byMME_UE, MME_UE may generate an “Implicit Response” in the form of‘x-a,x-b,x-c(Y)’. This “Implicit Response” is understood by the Basestation as a message comprising of allocated bearer resourcescorresponding to the value of ‘x’ to UE, and as a message comprising ofallocated bearer resources corresponding to the value of ‘x-a’, ‘x-b’,‘x-c’ for the relay nodes ‘P’, ‘Q’ and ‘R’ respectively.

Once MME_UE generates “IA Response Accept” message, it forwards to Basestation. “IA Response Accept” message as received by the Base stationcomprises of ‘S1-AP message for UE’, and ‘S1-AP message for RNs’. Basestation performs RRC configuration for the said downstream RN and thenforwards “IA Response Accept” message to the said RN. “IA ResponseAccept” message received by the said RN is different from the “IAResponse Accept” message received at the Base station. The “IA ResponseAccept” message received at the said RN is “IA Response Accept” messagereceived at the Base station without ‘bearer configuration’ for the saidRN. This is so because the S1-AP bearer configuration message for thesaid RN has been already used by the Base station. “IA Response Reject”message as received by the Base station comprises of S1-AP message forUE, and ‘RN NAS message for bearer resource reject’. Base stationforwards “IA Response Reject” message to RN. RN may use the S1-APmessage for UE to do RRC configuration.

In case of multiple relay nodes the ‘RR Request’ is received andunderstood by the MME_RNs. MME_RNs have complete knowledge of bandwidthusage of all the relay nodes (for e.g., relay nodes RN1, RN2). Then,based on the bandwidth requirement, bandwidth usage of the relay nodesand maximum bandwidth limit for the relay nodes, MME_RN2 processes andgrants the bearer request for the relay node RN2 and MME _RN1 grants thebearer request for the relay node RN1. In such cases MME_RN2 and MME_RN1 generates ‘RR Response Positive Ack’ message and forwards it toMME_UE. MME_UE generates “IA Response Accept” message and forwards it toBase station. “IA Response Accept” message as received by Base stationcomprises of: ‘S1-AP message for UE’ and ‘S1-AP message for RN1 andRN2’. Base station performs RRC configuration for the said downstreamRN2 and then forwards “IA Response Accept” message to the said RN2. “IAResponse Accept” message received by the said downstream RN2 isdifferent from the “IA Response Accept” message received at the Basestation. The “IA Response Accept” message received by the downstream RN2is “IA Response Accept” message received at the Base station without‘bearer configuration’ for the said downstream RN2. This is so becausethe S1-AP bearer configuration message for the said downstream RN2 hasbeen already used by the Base station.

Similarly, the said downstream RN2 performs RRC configuration for itsdownstream RN1 and forwards “IA Response Accept” message to it. The “IAResponse Accept” message received by the downstream RN1 is “IA ResponseAccept” received by the RN2 without ‘bearer configuration’ for the saiddownstream RN1. This is so because the S1-AP bearer configurationmessage for the said downstream RN1 has been already used by the RN2.Thereafter RN1 being the first upstream node for the said UE performsRRC configuration for the ‘S1-AP message for UE’ and forwards bearerconfiguration message to UE.

The MME_RNs may not grant bearer resources for any of the relay nodes(for e.g., RN1, RN2). In such cases MME_RNs generates ‘RR ResponseNegative Ack’ messages and forwards to MME_UE. MME_UE generates “IAResponse Reject” message and forwards it to Base station. “IA ResponseReject” message as received by Base station comprises of: ‘S1-AP messagefor UE’ and ‘RN NAS message for bearer resource reject’ for all the RNs'(e.g., RN1 and RN2). Base station forwards the received “IA ResponseReject” to the said downstream RN2.

The MME _RN2 may grant the bearer resources for RN2 and for some (e.g.,RN1), bearer resource is not granted. In such cases “IA Response Reject”message generated by MME_UE comprises of: ‘S1-AP message for UE’, ‘S1-APmessage for RN2’ for which the resources are granted, and ‘RN NASmessage for bearer resource reject’ for which bearer resources are notgranted. The S1-AP message for RN2 may be used by the Base station forRRC reconfiguration of the said RN2, and forward “IA Response Reject” toRN2. The “IA Response Reject” message received by RN2 is “IA ResponseReject” received by the Base station without ‘bearer configuration’ forthe said downstream RN2. This is so because the S1-AP bearerconfiguration message for the said downstream RN2 has been already usedby the Base station for RRC reconfiguration of the said RN2. The “IAResponse Reject” message received by RN1 further contains ‘RN NASmessage for bearer resource reject’ for RN1.

Another embodiment of the invention relates to the implementation of theabove described various embodiments using hardware and software. It isrecognized that the various embodiments of the invention may beimplemented or performed using computing devices (processors). Acomputing device or processor may for e.g., be general purposeprocessors, digital signal processors (DSP), application specificintegrated circuits (ASIC), field programmable gate arrays (FPGA) orother programmable logic devices, etc. The various embodiments of theinvention may also be performed or embodied by a combination of thesedevices

Further, the various embodiments of the invention may also beimplemented by means of software modules, which are executed by aprocessor or directly in hardware. Also a combination of softwaremodules and a hardware implementation may be possible. The softwaremodules may be stored on any kind of computer readable storage media,for example RAM, EPROM, EEPROM, flash memory, registers, hard disks,CD-ROM, DVD, etc.

The present invention also covers any conceivable combination of methodsteps and operations described above, and any conceivable combination ofnodes, apparatuses, modules or elements described above, as long as theabove-described concepts of methodology and structural arrangement areapplicable.

It should be further noted that the individual features of the differentembodiments of the invention may individually or in arbitrarycombination be subject matter to another invention. It would beappreciated by a person skilled in the art that numerous variationsand/or modifications may be made to the present invention as shown inthe specific embodiments without departing from the spirit or scope ofthe invention as broadly described. The present embodiments are,therefore, to be considered in all respects to be illustrative and notrestrictive.

We claim:
 1. A method for bearer management signalling in acommunication network, the method comprising of; Forming “Union ofResource (UR) Request” message in the Evolved Packet Edge (EPE), whereinEPE includes user equipment (UE) and at least one relay node (RN) andthe like; Transporting the “UR Request” message from the EPE via Basestation to managing entity of relay nodes (RNs) within EPC, wherein‘managing entity of RNs’ are network nodes that manage or administerRNs, like mobility management entity serving the relay node (MME_RN),serving gate way, packet gate way, PCRF, HSS or combination thereof; andReceiving “Implicit Admission (IA) Response” by the Base station for thetransported “UR Request” from one of the said management entity, whereinthe said management entity is the mobility management entity thatserves/manages all the entities in the EPE.
 2. A method for bearermanagement signalling in a communication network, the method comprisingof; Forming “Union of Resource (UR) Request” message in the EvolvedPacket Edge (EPE), wherein EPE includes user equipment (UE) and at leastone relay node (RN) and the like; Transporting the “UR Request” messagefrom the EPE via Base station to managing entity of relay nodes (RNs)within EPC, wherein ‘managing entity of RNs’ are network nodes thatmanage or administer RNs like mobility management entity serving therelay node (MME_RN), serving gate way, packet gate way, PCRF, HSS orcombination thereof; and Receiving “Implicit Admission (IA) Response” bythe Base station for the transported UR Request, from one of the saidmanagement entities within EPC wherein at least one of the saidmanagement entities is the mobility management entity notserving/managing the same entities in the EPE.
 3. The method of claim 1,wherein forming “UR Request” comprises of; Tagging the NAS messagereceived by the relay node, wherein tagging includes adding userequipment identity (UE_ID) with the said received NAS message, at leastin any one of the control plane protocol layers like S1-AP, SCTP, PDCP,RLC, MAC, PHY, preferably over NAS; Constructing an RN NAS message byencapsulating the received NAS message along with tag, wherein the NASmessage is UE NAS message when coupled to UE, and wherein the NASmessage is RN NAS message when coupled to UE via another relay node; andwherein UE_ID is RN_ID when coupled to UE via another relay node;Forwarding the said RN NAS message, now called as ‘tagged message’ tothe MME_RNs via Base station.
 4. The method of claim 2, wherein forming“UR Request” comprises of; Tagging the NAS message received by the relaynode, wherein tagging includes adding user equipment identity (UE_ID)with the said received NAS message, at least in any one of the controlplane protocol layers like S1-AP, SCTP, PDCP, RLC, MAC, PHY, preferablyover NAS; Constructing an RN NAS message by encapsulating the receivedNAS message along with tag, wherein the NAS message is UE NAS messagewhen coupled to UE, and wherein the NAS message is RN NAS message whencoupled to UE via another relay node; and wherein UE_ID is RN_ID whencoupled to UE via another relay node; Forwarding the said RN NASmessage, now called as ‘tagged message’ to the MME_RNs via Base station.5. The method of claim 1 further comprising of; Receiving the taggedmessage by MME_RN; Granting utmost “UR Request” by the said MME_RN,wherein granting includes storing relay node identities (RN_IDs),understanding, and generating “IA Response” message if accepted andgenerating ‘UE NAS message for bearer resource reject’ if rejecting forthe said received tagged message; and Forwarding to Base station oneamong the generated responses, which include ‘UE NAS message for bearerresource reject’ and “Implicit Admission Response” for the said EPEentities, wherein Implicit Admission (IA) response includes “IA ResponseAccept” and “IA Response Reject” messages.
 6. The method of claim 2further comprising of; Receiving the tagged message by MME_RNs;Understanding the said received tagged message, ‘un-tagging’ andforwarding ‘RN NAS Message’, forwarding ‘UE NAS Message’, forwardingidentities of MME_RNs to management entities serving the relay nodes andmanagement entity serving the user equipment respectively, wherein‘un-tagging’ includes, identifying ‘RN NAS Message’ ‘UE NAS Message’,identifying TAGs (UE_TAG) within the said received tagged message.Receiving ‘UE NAS Message’ by MME_UE and granting utmost “UR Request” bythe said MME_UE, wherein granting includes, understanding, rejecting,accepting, and generating ‘UE NAS message for bearer resource reject’ ifrejecting, generating relay node resource request (RR request) messagesfor granted resources by MME_UE, for MME_RNs identified by MME_RNidentities if accepting, for the said received message; Forwarding thegenerated ‘RR request’ message to MME_RNs identified by MME RNidentities; Receiving relay node resource response (RR response) fromMME_RNs for the forwarded ‘RR request’; Generating “IA Response” messageby MME_UE; and Forwarding to Base station one among the generatedmessages, which include ‘UE NAS message for bearer resource reject’ and“Implicit Admission Responses” for the said EPE entities by MME_UE,wherein Implicit Admission (IA) response includes “IA Response Accept”,and “IA Response Reject” messages.
 7. The method of claim 6 furthercomprising of; Receiving ‘RR Request’ message by MME_RNs from MME_UE;Granting utmost ‘RR Request’ by MME_RNs, wherein granting includesunderstanding, rejecting, and generating ‘RR Response’ message for thesaid received ‘RR Request’ message; and Forwarding one among thegenerated ‘RR Response’ message to MME_UE, wherein ‘RR Response’ messageincludes at least one among ‘RR Response Positive Ack’, ‘RR ResponseNegative Ack’.
 8. The method of claim 5 further comprising of; Receivingby the Base station, one among the responses generated by managemententities of EPE comprising of: ‘UE NAS message’ and “IA Response”wherein “IA Response” comprises of: “IA Response Accept”, “IA ResponseReject”; Performing RRC configuration for the relay node coupled to thesaid Base station if required, and forwarding to the said relay node “IAResponse” message for remaining EPE entities; Forwarding ‘UE NASmessage’ to UE via said relay node.
 9. The method of claim 6 furthercomprising of; Receiving by the Base station, one among the responsesgenerated by management entities of EPE comprising of: ‘UE NAS message’and “IA Response” wherein “IA Response” comprises of: “IA ResponseAccept”, “IA Response Reject”; Performing RRC configuration for therelay node coupled to the said Base station if required, and forwardingto the said relay node “IA Response” message for remaining EPE entities;Forwarding ‘UE NAS message’ to UE via said relay node.
 10. A bearermanagement signalling system for relay node in a communication networkcomprising of; A receiver for receiving NAS Message, “IA Response”message; A processor for tagging wherein, tagging includes adding userequipment identity (UE_ID) with the said received NAS message, at leastin any one of the control plane protocol layers like S1-AP, SCTP, PDCP,RLC, MAC, PHY, preferably over NAS; wherein the NAS message is UE NASmessage when coupled to UE, and wherein the NAS message is RN NASmessage when coupled to UE via another relay node; and wherein UE_ID isRN_ID when coupled to UE via another relay node; A processor forconstructing an RN NAS message by encapsulating the received NAS messagealong with the said TAG; A transmitter for transmitting RN NAS messagetowards the managing entity via Base station; A processor forunderstanding the received “IA Response” message and ‘NAS message’ fromBase station and performing RRC configuration if indicated in the said“IA Response” message; A transmitter for transmitting ‘NAS message’,‘radio bearer configuration message’, “IA Response” to EPE entities; andA memory that retains instructions for executing functions associatedwith the receiver, processor/processors, and transmitter and as well asmeasured or computed data that may be generated during executing suchfunctions.